Since the news outlets are focusing on the release of the Gospel of Judas, I thought it appropriate to post the following...
If you really want to know the story "behind" Judas Iscariot's betrayal of Jesus, you need to know the Old Testament.
In 2 Samuel 15 we read about the "betrayal" of David by Ahithophel.
2 Sam 15: 23 And all the country wept aloud as all the people passed by, and the king crossed the brook Kidron, and all the people passed on toward the wilderness...
30 But David went up the ascent of the Mount of Olives, weeping as he went, barefoot and with his head covered; and all the people who were with him covered their heads, and they went up, weeping as they went. 31 And it was told David, "Ahithophel is among the conspirators with Absalom." And
David said, "O LORD, I pray thee, turn the counsel of Ahithophel into foolishness."
Later, we learn of Ahithophel's fate; he hanged himself (2 Sam 17:23).
Jesus, the Son of David, is betrayed by a member of his inner circle. While his betrayer is out planning his demise, he, like David, goes to the Mount of Olives (Matt 27:30), crossing the Kidron valley (John 18:1). As David prayed that the Lord would confound Ahithophel's plans, Jesus similarly prays for deliverance (Matt 26:29-34). In the end, Jesus' betrayer's fate is the same as that of David's betrayer's: he "hangs" himself (Matt 27:5). We might also note that the women weep for Jesus as the people wept for David (Luke 23:27).
We need to always remember the importance of reading the New Testament in light of the Old Testament. For more on this, see the extensive collection of articles on methodology available on-line through the Saint Paul Center for Biblical Theology's website.